Test: Digestive System - MCAT MCQ

The Fehling's solution test is used to detect the presence of glucose. When glucose is present, the solution changes from blue-green to brick red, indicating a positive result.

The crown of the tooth is the visible part above the gum and is covered by enamel, the hardest substance in the human body, which protects the tooth from decay and damage.

Molars are designed with a larger surface area and multiple cusps, making them ideal for grinding food into smaller pieces, which facilitates further digestion by enzymes.

Saliva plays a crucial role in moistening food, which aids in forming a bolus for swallowing. It also contains enzymes like salivary amylase, which begins the digestion of starch.

The digestive system's main role is to convert food into simpler, absorbable forms that provide energy and nutrients to the body. This process involves various organs and enzymes that work together to ensure effective digestion and absorption.

Adult humans typically have 32 permanent teeth, including the wisdom teeth. This set of teeth is essential for efficient chewing and digestion of food.

The pyloric sphincter regulates the flow of partially digested food from the stomach into the duodenum, ensuring that food is released in a controlled manner for further digestion.

Hydrochloric acid is a key component of gastric juice, creating an acidic environment that activates digestive enzymes like pepsin and helps kill bacteria.

While the liver processes and regulates nutrients, it does not absorb them directly. Absorption occurs primarily in the small intestine; the liver's role is to manage the nutrients after absorption.

The large intestine primarily absorbs water and electrolytes from indigestible food matter, forming semi-solid faeces for elimination from the body.

Peristalsis refers to the wave-like muscle contractions that move food through the digestive tract, from the oesophagus to the intestines, facilitating the entire digestive process.

The small intestine is the main site for nutrient absorption due to its large surface area, which is enhanced by finger-like projections called villi. These adaptations allow for efficient uptake of amino acids, sugars, and fatty acids into the bloodstream.

Pepsin is the enzyme secreted in the stomach that breaks down proteins into smaller peptides. It is active in the acidic environment created by gastric juice.

Enzymes are proteins that act as catalysts in the digestive process, speeding up chemical reactions necessary for breaking down food without being used up in the process. They are specific to substrates and require optimal conditions to function effectively.

The tongue plays a vital role in manipulating food during chewing, aiding in tasting through taste buds, and helping form the food bolus for swallowing.

The vermiform appendix is considered a vestigial structure in humans, meaning it has no significant function in digestion or nutrient absorption. However, it may play a minor role in immune response.

The liver is responsible for detoxifying various substances, including drugs and alcohol, through metabolic processes and enzymatic reactions, making it crucial for maintaining overall health.

Pancreatic enzymes are crucial for digesting all macronutrients, including starch (amylase), proteins (trypsin), and fats (lipase), making them essential for complete digestion in the small intestine.

Milk teeth (deciduous teeth) and permanent teeth differ in number, function, and timing of eruption. Milk teeth are temporary and start appearing around 6 months, while permanent teeth replace them starting around age 6, typically totaling 32 in adults.

Bile, produced by the liver, emulsifies fats to increase their surface area for digestion and neutralizes the acidic content from the stomach, creating an alkaline environment in the small intestine for optimal enzyme activity.